I cut my teeth on the conventional theory of invasive plants and animals --- they outcompete native species and cause a decline in diversity.  Species like kudzu are able to run amok in our climate because they have no native diseases and predators to keep them under control, so they can swallow up whole hillsides.  The solution is eradication --- rip out every kudzu plant you see.

Lately, though, I've read several thought-provoking analyses of the invasive situation.  In Edible Forest Gardens, Dave Jacke and Eric Toensmeier assert that invasives only gain a foothold if the ecosystem is already out of whack.  According to these permaculturalists, the answer is not to spend weeks weeding Japanese stiltgrass out of your woods, but to discover what man-made change has made the invasive able to take over in the first place.  In their eyes, my original view of invasive control is like sticking a band-aid on an ecosystem suffering from chicken pox.

Hugh Raffles' recent New York Times article considers invasives in yet another light.  Raffles looks at species over a geologic time frame and reminds us that many of our "native" plants and animals originated elsewhere.  Nature is constantly in flux, wiping out species that aren't able to deal with changing conditions while replacing them with hardier cousins.  Taking a purely preservationist view of the earth --- trying to turn our current species assemblage into a static museum --- is bound to fail because species would migrate and die out even if we hadn't stirred the pot.

I think that both of these modern analyses of invasive species have merit...and problems.  I love the idea of looking for and trying to fix the underlying problems that promote the spread of invasives, but what if the problem is forest fragmentation and can't be dealt with on the personal scale?  Should we just throw up our hands and let our biodiverse woodlands turn into a monoculture?

And although Hugh Raffles' has a very good point about species flux over the course of geologic time, it's also true that extinction rates are currently at an all-time high, presumably because of human meddling.  Raffles' argument is also strongly colored by his recent experience becoming an American citizen, and I think that he needs to be a bit more careful about drawing parallels between people immigrating and whole species moving in.

When it comes right down to it, my difference of opinion with all three of these commentators is responsibility --- I think that humanity is ethically bound to take responsibility for the environmental devastation we've caused.  Looking at the bigger picture is always a good idea, but not if the exercise enables us to say "that kudzu-coated hillside isn't really our fault."  We broke it, so we should do everything we can to fix it, especially if we can come up with innovative answers like Peter Becker's Japanese Knotweed elimination campaign.

Maggie:

 3-30-01
I had to wait for the bus to come at noon, and ended up watching the hummingbirds swarm the feeders near the tables....  I sat there watching the birds and listening to the tourists compliment the soft drinks.

Eventually some terrible birdwatchers took the bench beside me....  The father was really pleased with his sons. Then they started talking about the birds calling them by numbers as found in the Common Costa Rica Bird Guide they carried. "There's a 24-7 page 7. Is that a 23-3?" Then a North American looking tour guide came over and started telling them all the names in numbers. "Here's a 23-9. Add that to your list."

The father gloated to the side to the young American tour guide, "Isn't it great? They're just kids." The funny thing is that when two yellow song birds came to the hummingbird feeder, the boys got all confused. "These hummingbirds aren't in the book. I cannot find any yellow hummingbirds." Eventually the guide explained that they were 40-24, not hummingbirds at all. "We should have known since they weren't hovering."

Anna:

In the Monteverde area, the pluses and minuses of ecotourism were painfully obvious.  On the one hand, tourism brought in foreign dollars that kept the standard of living in the area quite high and provided jobs that didn't destroy the local environment.  On the other hand, this same influx of capital often drives land prices out of the reach of the common man --- we learned that Monteverde acreages were significantly more expensive than those at home in central Appalachia.  If I couldn't afford to settle in Monteverde, could local Ticos?

And humanity was still impacting the forest, even if the trees weren't being cut down in droves to be replaced with banana trees (for export to the U.S., of course.)  Escaped house plants dotted the forest floor --- Wandering Jew (Tradescantia zebrina), an African Impatiens, and Polkadot Plant (Hypoestyes phyllostachya) were the most striking.  It became clear to me that wherever we go, we leave footprints behind us.



Although I believe that anything is better than central Appalachia's current core industry --- mountaintop removal coal-mining --- I wonder whether ecotourism is, in fact, the answer.  Will tour guides come from afar with the tourists, relegating the uneducated Appalachian to fast food server and taxi driver?  Or is there a way to lift up Appalachia's culture and ingenuity while still protecting the mountains we call home?

Although the animals are the most obvious feature of the east half of the River Trail, a few plants are bound to catch your eye.  In particular, you will have good views of an invasive plant that every naturalist should know.  Japanese Knotweed grows in dense stands along some sections of the Clinch, crowding out all native vegetation.  Although entirely unrelated, Japanese Knotweed bears a superficial resemblance to Giant Cane, and the knotweed tends to create conditions a bit reminiscent of the canebrakes that would have once grown in the same habitat.  Unfortunately, while canebrakes were home to many native plants and animals, Japanese Knotweed is a newcomer shunned by North America’s flora and fauna.

Once Japanese Knotweed catches a foothold along a river or streambank, it is nearly impossible to eradicate.  The plant spreads rapidly using underground rhizomes that can grow for up to two dozen feet in every direction from the parent plant, pushing new shoots up through pavement or anything else that gets in its way.  During floods, small sections of the Japanese Knotweed stems break free, sprouting and creating new infestations downstream.  Some land managers control their Japanese Knotweed populations using herbicides, but application is tricky along important waterways like the Clinch where chemicals dripping into the water could wipe out downstream mussel populations.

Scientists are stumped, but the ingenuity of common folks should not be taken lightly.  Peter Becker had been eating the young shoots of Japanese Knotweed along the streams near his home in Germany for years before he even realized that the plant was not native to the region.  He cooked up stems into delicious jams that tasted a bit like rhubarb as well as creating a savory relish to be eaten with meats and stir-fry.  He was thrilled to find out that Japanese Knotweed is a great source of resveratrol, a chemical that is also found in red wine and that many people think may be the cause of the wine’s healing properties.  Peter was less thrilled, though, when he learned that his gourmet feast came from a plant poised to wipe out a rare streamside plant community.

Rather than wringing his hands and giving in to the invasive plant’s spread, Peter created a profitable business that eradicated knotweed, fed the community, and lined his own pockets.  He chose a couple of pockets of knotweed to experiment on and then settled in for a season of hard work, cutting down the old stalks and burning them in the winter, then harvesting young shoots that sprouted back from the roots for ten weeks in the spring and summer.  The harvested shoots were turned into his jams and relishes and sold at farmer’s markets and then through a store and restaurant, while less tasty shoots that popped up later in the summer were turned into resveratrol supplements.  Meanwhile, native plant seeds were sown in the knotweed patch so that they could become established during the year of constant knotweed harvest.  Two years later, the knotweed in each patch had been eradicated at a profit of 140 euros (approximately $186) per square meter.  True German ingenuity!  A similar system could be implemented in our region to deal with our own knotweed infestation if anyone had the time and inclination to give it a shot.

Like identical twins separated at birth, China and the eastern United States share many similarities.  Our climates and geology are remarkably similar, and as a result plants and animals from China often find it easy to grow and thrive in Virginia’s landscape.  So I was not surprised to discover that most of our invasive plants originated in Asia.  Autumn-Olive and Japanese Honeysuckle are two members of this “Asian Invasion” that we could have done without.

Autumn Olive is easily recognized by the silvery scales that coat the undersides of the shrub’s leaves.  The plant was first introduced to the United States in 1830, but it seemed to be a well behaved guest until the Soil Conservation Service bred the “Cardinal” strain in 1963 and began to recommend planting Autumn Olive to reclaim strip mined land and to promote wildlife habitat.  As the Soil Conservation Service promised, the numerous red Autumn Olive berries were beloved by birds, who gobbled them up and spread the seeds throughout the eastern United States.  Today, Autumn Olive is expanding rapidly and is considered by many scientists to be the most troubling invasive shrub on the horizon.

Japanese Honeysuckle was introduced as an ornamental plant in 1806, and like Autumn Olive took decades before it started to encroach on native habitats.  Despite that fact that the vine is now listed as an invasive plant in four states and can be found choking out native plants in most old fields in our area, I have seen it for sale in local nurseries within the past year.

I consider both Autumn Olive and Japanese Honeysuckle to be cautionary tales --- the ecologist’s version of Little Red Riding Hood’s “grandmother” turning out to be a wolf.  I know I have already said this in an earlier chapter, but it bears repeating: Please try to stick with native plants in your landscaping, and whatever you do, steer clear of alien plants listed as providing “wildlife habitat.”  If the birds like their berries as much as the catalog promises, you may soon see that exciting ornamental cropping up in your neighbor’s forest.

The provenance of the Multiflora Rose patch near the top of the Cliff Trail is less mysterious because this prickly invasive is found in woodland edges throughout our region.  Like many invasives, Multiflora Rose was introduced on purpose, first as the rootstock for cultivated roses and then as erosion control, wildlife habitat, and hedging.  A good-sized Multiflora Rose plant can produce up to a million seeds per year, and songbirds enjoy munching on the rosehips, spreading the seeds to new locations.  As a result, Multiflora Rose has now infested 45 million acres of land in the eastern United States and is estimated to cost farmers $48 million dollars annually to control in West Virginia alone.  The ecological damage does not come with a price tag, but is equally staggering, with Multiflora Rose forming dense patches that outcompete native plants.

Enter a mysterious stranger --- the Rose Rosette Disease.  Like Superman, no one is quite sure what the Rose Rosette Disease is (maybe a virus?) or where it came from (somewhere west of Virginia?), but its effects are obvious.  Infected Multiflora Roses grow abnormally thickened and thorny or elongated stems, clusters of small branches called witches’ brooms, and reddish leaves.  Within a year or two, the infected rose dies, but not before transmitting the disease to its neighbors.

Ecologists are thrilled at the effects of this superhero disease, watching dense stands of Multiflora Rose die as the Rose Rosette Disease spreads east across the country.  Cultivated rose aficionados are less excited since Rose Rosette Disease can be just as devastating to their carefully bred rosebushes.  The disease does not really seem to care what we think, either way.  It has recently entered Virginia and will probably soon wipe out the patches of Multiflora Rose on Sugar Hill.  This misplaced plant, like maple sugaring in southwest Virginia, will soon be a thing of the past.

Tree of Heaven and Garlic Mustard are two alien invasive species that can be found along the south half of the Loop Trail.  The Tree of Heaven not only outcompetes native trees, its roots also exude a chemical that poisons plants trying to germinate in its shadow --- a trait known as allelopathy, which may be familiar to people who have tried to plant a garden near a Black Walnut.  Tree of Heaven quickly forms dense stands in open areas and is extremely difficult to eradicate since the trees will resprout from their stumps if cut and will also spread rapidly through wind-dispersed seeds.  The tree is easily identified by its divided leaves and by the foul odor given off by broken twigs.

Although Tree of Heaven is troublesome, Garlic Mustard has Appalachian ecologists terrified.  This little plant does not seem very dangerous at first glance, and its leaves are tasty to nibble on as you walk down the trail.  But unlike most of our invasive species that die back as soon as a mature forest begins to shade the forest floor, Garlic Mustard is able to invade dense forests where it overruns our stunning displays of early spring ephemerals.  In many moist forests in our region, the ground is now covered by a nearly unbroken stretch of Garlic Mustard.  The best offense is a good defense --- if you notice a few Garlic Mustard plants in your woods, be sure to pull them up before they go to seed.  More dense stands of the invasive require multiple years of mowing, pulling, or even herbicide treatment before they are fully eradicated.

Old fields and early successional forests are a great place to look for interesting plants and animals that cannot be found in more mature woods.  However, these recently disturbed areas are also more likely to be home to alien invasive species --- plants and animals that originated in Europe, Asia, or elsewhere and have gone wild in our woods and fields.  Some alien species sit exactly where you put them --- like the daffodils you plant in your flower bed --- but others are invigorated by their new home and spread like wildfire, often crowding out native species in the process.  Kudzu is an extreme example of an alien invasive species that wipes out everything in its path.  This type of alien invasive species is one of the biggest threats our native ecosystems face.

Why do alien invasive species grow so well in our area?  Nature is made up of a series of checks and balances that prevent any one plant or animal from dominating all others.  If a plant does very well, chances are an insect or fungus will come along and eat it up or make it sick.  But when a plant from China is plopped down in the Virginia mountains, it leaves its predators and diseases behind in China.  All around it, Virginia plants are struggling just to stay afloat, but the Chinese plant is untouched by Virginia insects and diseases, none of which know what to do with the odd plant.  Before you know it, the Chinese plant has spread across the whole state and is threatening to wipe out every native plant in its path.

Most of our invasive species were purposefully introduced by people who thought the plants would be a nice addition to their garden or useful for some other purpose.  Scientists find it hard to predict which species will become invasive pests and which ones will sedately sit in your garden like a daffodil, so the best option is to landscape with native plants whenever possible.